InvalidOperationException updating an entity with CurrentValues.SetValues throws InvalidOperationException when the SetValues parameter does not contain a required field data.

[alexdrl]

I am writing a custom save generic method for our framework in EF Core. The idea is to have a method that can make partial updates

The method is working with simple entities but throws an InvalidOperationException when the entity in entitiesAndProperties does not contain a required field data. It should not be a problem, because the entity already exists in database with the required field value, contextEntity reflects that, but seems the CurrentValues.SetValues overrides this.

If you are seeing an exception, include the full exceptions details (message and stack trace).

Exception message:
'The property 'Name' on entity type 'User' is marked as null, but this cannot be saved because the property is marked as required.'

Stack trace:
   at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.InternalEntityEntry.HandleConceptualNulls()
   at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.GetEntriesToSave()
   at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChanges(Boolean acceptAllChangesOnSuccess)
   at Microsoft.EntityFrameworkCore.DbContext.SaveChanges(Boolean acceptAllChangesOnSuccess)

Steps to reproduce

Those are the custom entity method and clases.

public IEnumerable<T> UpdateEntitiesByProperties(IEnumerable<UpdateByPropertiesData<T>> entitiesAndProperties)
        {
            List<T> entities = new List<T>();

            // TODO: (Error Management) Decide what to do with null parameters
            if (entitiesAndProperties?.Any() != true)
            {
                return entities;
            }

            foreach (UpdateByPropertiesData<T> entityAndProperties in entitiesAndProperties)
            {
                T contextEntity = this.context.Find<T>(entityAndProperties.Entity.Id);

                EntityEntry<T> changeTrackerEntityEntry = this.context.Entry(contextEntity);

                changeTrackerEntityEntry.CurrentValues.SetValues(entityAndProperties.Entity);

                // TODO: Review the possibility of having a local copy of the entityEntry modified
                // properties, for not setting them to false in this foreach. This will fix the edge
                // case when we call this method two times with the same entity and different data,
                // in which case, data is lost.
                foreach (PropertyEntry property in changeTrackerEntityEntry.Properties.Where(p => !p.Metadata.IsConcurrencyToken))
                {
                    property.IsModified = entityAndProperties.UpdatedProperties.Contains(property.Metadata.Name);
                }

                entities.Add(contextEntity);
            }

            return entities;
        }


 public class UpdateByPropertiesData<T>
    {
        /// <summary> Initializes a new instance of the <see cref="UpdateByPropertiesData{T}"/> class. </summary>
        public UpdateByPropertiesData()
        {
        }

        /// <summary> Initializes a new instance of the <see cref="UpdateByPropertiesData{T}"/> class. </summary>
        /// <param name="entity">
        ///     The entity.
        /// </param>
        /// <param name="properties">
        ///     The updated properties.
        /// </param>
        public UpdateByPropertiesData(T entity, IEnumerable<string> properties)
        {
            this.Entity = entity;
            this.UpdatedProperties = properties;
        }

        /// <summary> Gets or sets the entity with the updated properties. </summary>
        /// <value> The entity with the updated properties. </value>
        public T Entity { get; set; }

        /// <summary> Gets or sets the updated properties in string format. </summary>
        /// <value> The updated properties in string format. </value>
        public IEnumerable<string> UpdatedProperties { get; set; }
    }

If I change the code to this, it is working properly, but it uses reflection, and not seems that Smart as SetValues. With the SetValues documentation I thought that I could do what I did before... I thought that the ChangeTracker only updated the IsModified properties...

public IEnumerable<T> UpdateEntitiesByProperties(IEnumerable<UpdateByPropertiesData<T>> entitiesAndProperties)
        {
            List<T> entities = new List<T>();

            // TODO: (Error Management) Decide what to do with null parameters
            if (entitiesAndProperties?.Any() != true)
            {
                return entities;
            }

            foreach (UpdateByPropertiesData<T> entityAndProperties in entitiesAndProperties)
            {
                T contextEntity = this.context.Find<T>(entityAndProperties.Entity.Id);

                EntityEntry<T> changeTrackerEntityEntry = this.context.Entry(contextEntity);

                changeTrackerEntityEntry.CurrentValues.SetValues(entityAndProperties.Entity);

                // TODO: Review the possibility of having a local copy of the entityEntry modified
                // properties, for not setting them to false in this foreach. This will fix the edge
                // case when we call this method two times with the same entity and different data,
                // in which case, data is lost.
                foreach (PropertyEntry property in changeTrackerEntityEntry.Properties.Where(p => !p.Metadata.IsConcurrencyToken))
                {
                    if (entityAndProperties.UpdatedProperties.Contains(property.Metadata.Name))
                    {
                        property.CurrentValue = typeof(T).GetTypeInfo().GetDeclaredProperty(property.Metadata.Name).GetValue(entityAndProperties.Entity);
                    }
                }

                entities.Add(contextEntity);
            }

            return entities;
        }

This is the reproducing code. It seems that it is simple to reproduce, but if you really need i could try to make a simple .NET Core console app which reproduces this.

using (BaseContext context = new BaseContext(connectionProvider))
            using (IUnitOfWork unitOfWork = new UnitOfWork<BaseContext>(context))
            {
                User changedUser = new User(Guid.Parse("11111111-1111-1111-1111-111111111111"), Guid.NewGuid());
                changedUser.LongName = "NewLongName";

                UpdateByPropertiesData<User> ubpdData = new UpdateByPropertiesData<User>(changedUser, new string[] { "LongName" });

                entitiesList.AddRange(unitOfWork.GetRepository<User>().UpdateEntitiesByProperties(new UpdateByPropertiesData<User>[] { ubpdData }));

                unitOfWork.SaveChanges();
            }

Further technical details

EF Core version: 1.1.2
Database Provider: Microsoft.EntityFrameworkCore.SqlServe
Operating system:
IDE: Visual Studio 2017 15.2